Abstract
Ligation of the antigen receptor on B cells induces the rapid phosphorylation of tyrosine on a number of cellular proteins. A monoclonal antibody that recognized a tyrosine-phosphorylated cell surface protein that was present in activated B cells was generated. Amino acid sequence analysis showed that this 140-kilodalton protein was CD22, a B cell-specific cell surface glycoprotein and putative extracellular ligand of the protein tyrosine phosphatase CD45. Tyrosine phosphorylation of CD22 may be important in B cell signal transduction, possibly through regulation of the adhesiveness of activated B cells.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Antigens, CD / metabolism*
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Antigens, Differentiation, B-Lymphocyte / metabolism*
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B-Lymphocytes / immunology*
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Burkitt Lymphoma
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Cell Adhesion Molecules*
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Chymotrypsin / metabolism
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Humans
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Immunoblotting
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Immunosorbent Techniques
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Lectins*
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Lymphocyte Activation*
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Peptide Mapping
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Phosphorylation
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Phosphotyrosine
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Sialic Acid Binding Ig-like Lectin 2
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Signal Transduction / physiology
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Tumor Cells, Cultured
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Tyrosine / analogs & derivatives*
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Tyrosine / metabolism
Substances
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Antigens, CD
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Antigens, Differentiation, B-Lymphocyte
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CD22 protein, human
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Cell Adhesion Molecules
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Lectins
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Sialic Acid Binding Ig-like Lectin 2
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Phosphotyrosine
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Tyrosine
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Chymotrypsin